[openvrml-develop] Re: Speed Issues

[Damian M. <da...@er...>]

> Also, the initial display of the VRML file, from load, has both texturing
> and alpha-blending turned on.
>
> How would I make the start-up ignore these without affecting the Viewer's
> ability to turn them back on?

That appears to be largely a waste of time.

The killer, at least for the type of data we have, appears to be the
call to

	gluScaleImage(....)

Eliminating this call during operations reduces load time from 24 seconds
down to 15 seconds.  Mind you, the only way to properly eliminate this
call is to preprocess your images before to ensure your images are nice
sizes when they hit memory.  That almost seems like a mandatory item when
using OpenVRML.  Preprocess your images or suffer a performance hit.

However, a quick perusal of the code shows us that in the line where this
routine is (effectively) called that we have a comment there which warns
us ....

	      // Always scale images down in size and reuse the same pixel
	      // memory. This can cause some ugliness...

Can anybody enlighten me as to the ugliness that this will cause?

Thanks - Damian (McGuckin)

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